Elenco Electronics EP-130 - Adjustable R-C Oscillator

-
8
2-
The “R-C” in this ex
p
eriment’s name re
p
resent
s
res
i
stance-capac
i
tance.
Y
ou
h
ave seen
h
ow vary
i
n
g
resistance and capacitance can affect the pulsing
action of an oscillator. This experiment lets us se
e
the e
ff
ects when we can alter the stren
g
ths o
f
bot
h
res
i
stors an
d
ca
p
ac
i
tors
.
Vi
ew t
h
e sc
h
emat
i
c.
Y
ou can see t
h
e sw
i
tc
h
l
ets yo
u
choose between two different capacitors.
C
onnecting
terminals 13 and 14 adds another resistor to th
e
c
ir
cu
it.
B
u
ild
t
h
e c
i
rcu
i
t an
d
set t
h
e sw
i
tc
h
to pos
i
t
i
on
B.
P
ress t
h
e
k
ey, an
d
l
eave term
i
na
l
s 13 an
d
1
4
unconnected. What kind o
f
sound comes
f
rom th
e
speaker
?
Now set the switch to A and press the ke
y
another time. Is there any di
ff
erence in the sound
?
N
ow attac
h
term
i
na
l
s 13 an
d
14 an
d
press t
h
e
k
ey.
Try both settin
g
s of the switch with terminals 13 an
d
14
a
tt
ac
h
ed
a
n
d
see
wh
a
t o
ccu
r
s.
Which combination gives you the highest tone
?
Th
e
lowest? What does this show you about ho
w
ca
p
acitors and resistors affect each other? Tak
e
meticulous notes about the e
ff
ects o
f
the di
ff
eren
t
value capacitors and resistors
.
N
otes
:
EXPERIMENT #
6
4: ADJ
US
TABLE R-
C
OSC
ILLAT
OR
Wiring
S
equence
:

1
-2
9

2
-
30

3-47-11
0

4-
8
7-
89
-1
38

5
-101-105-10
9

13
-
88

1
4-90-46-13
2

48-12
1

1
02-13
1

106
-
133

119
-
137
Schemati
c